12,019 Holocene Calendar - LENS Traffic: 2019 Calendar (8.5" x 11") (21.59 x 27.94 cm) 1st Edition

So, I was looking for an interesting calendar for the human era. Surprisingly little information and few products. I order this and what do I find? Somehow we have an extra couple of days. February has 28 days period. The only difference between this and regular calendar should be that # 1 before the year 2019. How did you mess that up?